1 Prepare project
npm install -g truffle
mkdir MyToken && cd MyToken
truffle init
npm init -y
2 Programming ERC-20
pragma solidity ^0.5.16;
import './SafeMath.sol';
contract Token {
using SafeMath for uint;
event Transfer(
address indexed _from,
address indexed _to,
uint256 _value
);
event Approval(
address indexed _owner,
address indexed _spender,
uint256 _value
);
string public symbol;
string public name;
uint8 public decimals;
uint public totalSupply;
mapping(address => uint) balances;
mapping(address => mapping(address => uint)) allowed;
constructor() public {
symbol = 'XXX';
name = 'XXX Token';
decimals = 18;
totalSupply = 1000000000 * 10**uint(decimals);
balances[msg.sender] = totalSupply;
emit Transfer(address(0), msg.sender, totalSupply);
}
function balanceOf(address _owner)
public
view
returns (uint balance)
{
return balances[_owner];
}
function transfer(address _to, uint _value) public returns (bool success) {
balances[msg.sender] = balances[msg.sender].sub(_value);
balances[_to] = balances[_to].add(_value);
emit Transfer(msg.sender, _to, _value);
return true;
}
function transferFrom(address _from, address _to, uint _value)
public
returns (bool success)
{
balances[_from] = balances[_from].sub(_value);
allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
balances[_to] = balances[_to].add(_value);
emit Transfer(_from, _to, _value);
return true;
}
function approve(address _spender, uint _value)
public
returns (bool success)
{
allowed[msg.sender][_spender] = _value;
emit Approval(msg.sender, _spender, _value);
return true;
}
function allowance(address _owner, address _spender)
public
view
returns (uint remaining)
{
return allowed[_owner][_spender];
}
}
3 Config truffle-config.js
const mnemonic = 'your 12 words';
const HDWalletProvider = require('@truffle/hdwallet-provider');
module.exports = {
networks: {
// Useful for testing. The `development` name is special - truffle uses it by default
// if it's defined here and no other network is specified at the command line.
// You should run a client (like ganache-cli, geth or parity) in a separate terminal
// tab if you use this network and you must also set the `host`, `port` and `network_id`
// options below to some value.
//
// development: {
// host: "127.0.0.1", // Localhost (default: none)
// port: 8545, // Standard Ethereum port (default: none)
// network_id: "*", // Any network (default: none)
// },
// Another network with more advanced options...
// advanced: {
// port: 8777, // Custom port
// network_id: 1342, // Custom network
// gas: 8500000, // Gas sent with each transaction (default: ~6700000)
// gasPrice: 20000000000, // 20 gwei (in wei) (default: 100 gwei)
// from: <address>, // Account to send txs from (default: accounts[0])
// websockets: true // Enable EventEmitter interface for web3 (default: false)
// },
// Useful for deploying to a public network.
// NB: It's important to wrap the provider as a function.
ropsten: {
provider: () => new HDWalletProvider(mnemonic, `https://ropsten.infura.io/v3/YOUR_PROJECT_ID`),
network_id: 3, // Ropsten's id
gas: 5500000, // Ropsten has a lower block limit than mainnet
confirmations: 0, // # of confs to wait between deployments. (default: 0)
timeoutBlocks: 50, // # of blocks before a deployment times out (minimum/default: 50)
skipDryRun: true // Skip dry run before migrations? (default: false for public nets )
},
// Useful for private networks
// private: {
// provider: () => new HDWalletProvider(mnemonic, `https://network.io`),
// network_id: 2111, // This network is yours, in the cloud.
// production: true // Treats this network as if it was a public net. (default: false)
// }
},
// Set default mocha options here, use special reporters etc.
mocha: {
// timeout: 100000
},
// Configure your compilers
compilers: {
solc: {
// version: "0.5.1", // Fetch exact version from solc-bin (default: truffle's version)
// docker: true, // Use "0.5.1" you've installed locally with docker (default: false)
// settings: { // See the solidity docs for advice about optimization and evmVersion
// optimizer: {
// enabled: false,
// runs: 200
// },
// evmVersion: "byzantium"
// }
}
}
}
4 Add 2_deploy_contracts.js
const Token = artifacts.require('Token');
module.exports = (deployer) => {
deployer.deploy(Token);
};
5 Deploy contracts
truffle migrate --network ropsten (--reset)
